Many mechanisms for transporting toner (developer) by means of traveling-wave electric fields (as disclosed in, for example, Japanese Patent Application Laid-Open (kokai) Nos. 2002-99143, 2002-351218, and 2003-15417) are conventionally known for use in image forming apparatus.
In such a mechanism, a large number of strip-shaped electrodes are juxtaposed in a row on an electrically insulative substrate. A wiring pattern is provided externally of an array of the strip-shaped electrodes at an end portion of the substrate with respect to the width direction of the substrate, the width direction being orthogonal to the direction along which the strip-shaped electrodes are arrayed.
In such a mechanism, polyphase AC voltages are sequentially applied to the plurality of strip-shaped electrodes via the wiring pattern, whereby traveling-wave electric fields are generated. By the action of the traveling-wave electric fields, charged toner particles are transported in a predetermined direction.